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Wave forecasting for offshore operations

Accurate forecasting of marine weather conditions is vital for the effective and safe management of offshore operations. However, at forecast horizons beyond 2–3 days, marine weather forecasts have a degree of uncertainly due to ‘chaos’ caused by the physical characteristic of the atmosphere-ocean system.

MetraWeather's Downscaled Super Ensemble (DSE) is a powerful technique that quantifies that chaos and defines the likely envelope of sea state conditions over a forecast horizon.

Ensemble forecasts are the result of weather prediction models based on a slightly perturbed initial condition, thereby simulating the inherent chaos in weather. DSEs provide site-specific forecasts of winds and waves from multiple sources, and make dynamical and statistical adjustments to scale them to the exact location of interest.

The result is 78 individual forecasts of the winds and waves for a given location – displayed as ‘spaghetti’ plots from which the probability of non-exceedance is calculated. Forecasts are provided through MetOceanView, a dedicated web portal providing access to detailed and reliable weather forecasts.

Wave forecast DSE has been deployed in critical offshore operations in Australia and New Zealand. On two of these projects, DSE is being used to ensure that multi-day operations are only conducted during low energy wave conditions, and the 90th percentile non-exceedance wave height is used as the safe operational threshold.

On other projects, DSE is being used to forecast the onset of potentially dangerous sea states that require action to be taken several days before a storm arrival. Here, the maximum predicted wave condition defines the threshold of concern.